


Nature vs. Nurture

by StarlightSystem



Category: Gravity Falls
Genre: Alternate Universe - Quarantine (Gravity Falls), Alternate Universe - Transcendence (Gravity Falls), Dark Alcor, Darker variant, Gen
Language: English
Status: Completed
Published: 2020-04-08
Updated: 2020-04-08
Packaged: 2021-03-01 19:08:55
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,859
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23532100
Author URL: https://archiveofourown.org/users/StarlightSystem/pseuds/StarlightSystem
Summary: Naomi Argenta sees a side of her brother that she's never seen before, and starts to question whether Dipper really is who she thinks he is.(Or: Noie's Brother if it happened in Darker Quarantine AU)
Comments: 14
Kudos: 46





	Nature vs. Nurture

**Author's Note:**

  * For [ToothPasteCanyon (DannyFenton123)](https://archiveofourown.org/users/DannyFenton123/gifts).
  * Inspired by [Noie's Brother](https://archiveofourown.org/works/17593598) by [ToothPasteCanyon (DannyFenton123)](https://archiveofourown.org/users/DannyFenton123/pseuds/ToothPasteCanyon). 



> Okay, one of the things I love about TAU is how much background knowledge goes into reading a fic. Like:
> 
>   * [Transcendence AU](https://transcendence-au.tumblr.com/) is a Gravity Falls AU where Dipper becomes a demon when Bill dies.
>   * [Noie's Brother](https://archiveofourown.org/works/17593598) is a story about Dipper wiping his memory, pretending to be human, and growing up alongside a reincarnation of Mabel.
>   * [Quarantine AU](https://quarantine-au.tumblr.com/) is a sub-AU of Transcendence where Ford isolates Dipper from the rest of his family either through guilt or through actually locking him away.
>   * [Darker variant](https://quarantine-au.tumblr.com/post/614576078056488960/i-know-quarantine-au-has-a-lot-of-variants-and) Quarantine is specifically the version where Dipper is so traumatized by Ford that he ends up permanently stuck in Evil Demon Mode.
> 

> 
> Sound good? Cool. Happy birthday Tooth!

If there was one thing Naomi Argenta knew for certain it was that she did _not_ trust that angel.

Oh, she knew she was supposed to. Her teachers in middle school had done their best to drill it into her head why it was important that there was an angel stationed at every high school in the country. Something about how teen brains were fickle and more prone to being corrupted by preter forces. She didn’t quite understand that part, especially since she’d never met a preter in her life, but if President Chancellor III said it was important she guessed she had no choice but to put up with it.

But still, she absolutely didn’t trust it, for a number of reasons.

 **Reason 1** : It was creepy.

Every day when she walked past it at the school gates, she could feel it watching her. It didn’t actually turn to look at her or anything -- in fact it never seemed to move at all -- but still she could sense its presence. And it wasn’t even only in the mornings: sometimes she got the same vibe she got from the angel just from random people in the halls or in class. Sometimes, she could even make out a faint glowing light around those people. And that kinda freaked her out.

Also, she seemed to be alone in feeling this way. She’d asked a couple of people in class -- not friends, no, she didn’t really, have, any, well you know -- but they had no idea what she was talking about. She may have let it slip to the school nurse after the incident with the jocks and the soccer ball, and that didn’t go well either, because as it turned out the counselor’s family were all devout angel worshippers. So she seemed to be alone in feeling stalked by this angel.

“Noie?”

That led to the next thing, which was:

 **Reason 2** : It kept talking to her.

And none of what it said made the slightest bit of sense.

_My apologies, child, for the long and painful road you are on. I’m doing the best I can to grant you salvation, but it isn’t easy you see._

All she wanted was to walk into school in the morning and not have it be a big deal, but increasingly often she’d get this weird probing sensation and then -

_Freedom is within your grasp, but only if you heed my warnings. Humans, while charming, are so very weak. You must let me guide you, for my power is much stronger._

She had to wonder whether or not this was normal. Was it really the president’s intention that if a high schooler got hit in the head during gym class and had to go to the nurse, she’d have to deal with an adult in scrubs with a halo whispering stuff like -

_The beast is so close that I fear it may be too much and that you’ll succumb to its darkness. Trust me, my child, that I am working as hard as I can to arrange divine intervention._

“Hey, Noie. Are you zoning out again?”

And that somehow led to the final thing -- something she couldn’t be 100% sure was actually the angel’s fault but which had been happening more and more often lately -- and that was:

 **Reason 3** : It was making her brother go… weird.

“Helloooo? Earth to Noie!”

It took Noie a moment to parse the voice and take in the scene in front of her. Dipper was sitting across the lunch table from her, a chicken nugget in hand and a concerned look on his face.

“Uhh, sorry bro. What’s going on?”

“You had that weird ‘glazed over’ look you get when you’re obsessing over something.”

Noie shrank a little, but tried to wave it off. “It’s nothing! Probably just this gross school cafeteria food. Here,” she added, pushing the tray of food over to him, “you eat it.”

“What? I’m not gonna eat your gross nuggets! Besides, you can’t skip lunch! You’re the one always hounding me for not eating enough!”

She laughed half-heartedly and took the tray back. “Guess you’ve got a point.” She dipped a nugget into her ketchup and took a bite. She wondered if chicken was really supposed to taste like plastic, and whether it was actually chicken at all or just

_a liar, a deceiver of mortals, hiding its true nature under a familiar skin until the moment at which it strikes and all is lost -_

She buried her face in her hands. Because that was the other thing. She trusted her brother more than anyone else in the world, but she couldn’t tell him what she was thinking about. And that’s because the angel _loved_ to tell her -- in explicit detail -- that Dipper -- _her brother!_ \-- was not actually human, but in fact some sort of horrible monster in disguise. A _demon_.

Which was 1000% insane on the face of it, obviously.

...Probably.

She hoped.

Okay she really shouldn’t let weird ideas get under her skin so easily but ever since the angel had started thought-beaming it into her head on the daily it had really set her on edge and that’s part of why she hated the damn thing so much because it was making her feel uneasy around her own bro-

“Noie…? Are you okay?”

Picking her head up, Noie blinked vacantly, then yelped when Dipper flicked a french fry at her face. “What was that for?”

He crossed his arms. “It’s for being weird and not telling me why. Seriously, what’s up?”

“I, uh,” she stammered, avoiding meeting his eyes. “I’ve got a headache. You know how it is!”

“You never get headaches…”

She pouted. “Well I do now! My brain’s got extreme tiredness and stuff. It must be from all of this grilling! Hey, I’ve got a great idea! Can we talk about something else? Like, whatcha reading there?” She craned her head, trying to catch sight of the cover of his book. “Catching up on homework?” she guessed, reaching a hand over.

“Come on, Noie, you know I did my homework.” He swatted her hand away and hugged the book to his chest, face turning light pink. “It’s nothing. Hey, did _you_ do _your_ homework?”

“Someone’s being defensive!” she trilled. “You know, if it’s one of those detective novels you’re always reading, I wouldn’t mind hearing about it.”

“... You sure you’re not just gonna call me a loser?” He left the ‘like everyone else’ unsaid, but she heard it anyway.

“Swear on my mother’s grave.”

He spluttered in surprise at that. “You can’t say that when our mother is _actually_ _dead_ , Noie! It doesn’t work that way!”

Noie threw her hands up. “I’m just saying! That’s how serious I am!”

He looked at her suspiciously for a moment, but the excitement to talk about his book appeared to outweigh any offense taken. “Okay, so, Professor Quisdolor got hired by the National Security Agency to try and find these super secret encryption certificates that someone stole. See, he _thinks_ the culprit is this lady in Venice -- which was a city built on top of a bunch of canals before it sank into the ocean a few hundred years ago -- and so he goes to spy on this lady but in the process he finds out he’s being watched, and the person spying on him _is also from the NSA_! I think the lady’s innocent and the government never had the certificates to begin with, that’s my guess.”

Noie nodded judiciously throughout his speech. “Oooh, intriguing. You know what’d be really cool? If it turned into a court drama at the end! You’d have to be _really_ smart to win against the government in a court case! I’d totally read that.”

“Well… I don’t think it ends that way. This author really likes ending their books by using memory wipe spells on the villains, which makes them forget how to be evil because evilness is a learned trait or something. It’s kinda disappointing. The rest of the story is always really good but the endings are… eh.”

Noie leaned back in her chair and put her legs up on the table. “That’s what fanfiction is for, bro! You find something dark and depressing and you pave right over it with glitter and sparkles and thrilling but wholesome moments!”

“That sounds pretty good,” he said with a smirk. “Hey, you should write it! I’d totally read your glittery detective fanfiction.”

Noie’s smile faltered. “Uh, well, I dunno. I’m not really good at writing. You should probably do it. It’d end up stupid if I did it.”

“Don’t put yourself down.”

“Dipper…”

“No! You’re smart and creative. If you wanted to write fanfiction you’d be great at it.”

She shrugged. “Grandpa says -”

“Grandpa’s… grandpa’s kind of a jerk to you sometimes!” Dipper put his book down and started pacing next to the table. “I mean- I mean he keeps comparing you to me and saying you don’t do enough schoolwork and- and if he told you that you’re not smart and creative then that’s not -”

“Whoa, whoa!” Noie cut in, putting her feet back down. “He’s never said anything like that to me. It’s just sometimes I feel like he does. That’s all.”

He looked up, took in her concerned expression, and deflated. “Okay. Sorry, it’s just… not fair. You _are_ smart and creative and you should get to feel like it.”

“Yeah, well, maybe I’m not the _worst_ …” She pulled a pencil from her backpack and doodled a pair of stick figures on a napkin. “Look! It’s us!”

Grinning, Dipper got back in his seat and took the napkin from her. “Wow, it’s an incredible likeness! You think Grandma and Grandpa will have space on their fridge for this one?”

“And take down one of the depressing old newspaper clippings they’ve got up on there? Not a chance!” He gave her back the napkin and they shared a giggle. The school bell chose that moment to ring, and all around them people started gathering up their food and returning to the building. Dipper stood up too, but Noie lagged behind, just staring at the napkin drawing.

Hand in hand, brother and sister.

Two human siblings.

“Hey, bro. Thanks for looking out for me. Means a lot.”

Dipper looked back and twisted his face up. “Yeah. Thanks, uh -” (he glanced at the book tucked under his arm) “thanks for looking out for me too. Mystery Twins forever?”

Laughing, Noie stood up with her tray and awkwardly linked arms with her brother. “I still don’t get that name, but sure. Mystery Twins forever.”

He raised an eyebrow and slipped his arm out of hers. “You’re ridiculous. We’re gonna drop our food if we walk like that. Come on, we’re going to be late for class.”

They kept chatting as they walked back to the building, and some of the stress that had been building up in Noie’s head dissipated. For a little while, Noie could just forget about the angel and goof around with her brother.

* * *

As they headed toward the entrance of the school after class, Dipper closed his eyes and let out a grunt. Noie quickly looked up and stopped him just before he walked into a pole.

“Hey, Dipper…” she asked cautiously. “You okay?”

“Mm..mfn…” Eyes still closed, he rubbed his temples and cringed. “Head just started hurting.”

Noie’s heart sank. “Let’s get you home,” she said wrapping one arm around him and starting to walk again. “I’ll guide -- I mean get -- I’ll get you home. You don’t think you’ll be sick, right?”

He grunted again, but let his sister move him through the double doors onto the front lawn. “I… don’t think so. I dunno… Head really hurts. Can feel… a lot of magic nearby…”

Noie felt a familiar creeping sensation roll over her skin. “Yeah I wonder why,” she mumbled under her breath. She took her eyes off Dipper and saw the angel, standing immobile as ever near the entrance, watching them go by, doing… whatever it was doing to him. She felt it start to tap on her mind so it could whisper more mystical demeaning garbage and she scowled.

_Heed my warning, little one, you are in terrible danger -_

“Nope! Bye!” she yelled, and rushed Dipper to the bus. He hadn’t said a word since they left the building and was starting to let out little moans of pain. She was so used to it at this point that it was almost numbing to hear.

The bus driver watched them get on the bus and gave Noie a sad, knowing smile. Right. He’d seen this happen practically every day. She flashed something that felt vaguely like a smile back, and guided Dipper to a row near the back of the bus. Setting him in the window seat and letting him lean against the window before sitting in a seat herself, she put her backpack on the floor and pulled her knees to her chest. The bus jolted before pulling away, and finally Noie could be alone with her thoughts without that stupid angel listening in.

Although she wasn’t sure what to think about now that she had the chance. None of what came to mind was particularly pleasant.

Like how it wasn’t fair that she had to be worried about her mind being invaded while at school.

Or that she had literally no one she could talk to about this.

And how it was stupid that she kept second-guessing herself over and over again, because damn it she _knows_ who her brother is, so why was she getting herself into such a state about it?

“What… the fuck…”

Noie blinked and looked at Dipper, still slumped uncomfortably in the seat. “Did you say that, bro?”

A long pause. He didn’t seem to be moving at all, but it had sounded an awful lot like his voice. “Bro?” she asked again, giving him a light nudge with her hand.

“Oh yeah,” he murmured, his voice quiet and gravelly. ”Bro. I remember that. Fucking hilarious.”

Noie’s pulled her hand back. “Uh… what?”

Dipper’s eyes flashed open, and her blood ran cold. Black sclera and glowing gold irises. It was happening again. Whatever thing the angel did to him was making him go weird.

“I said it’s funny,” he replied, quietly enough that no one else could hear him. “That you’re falling for this. Damn I’m good.”

Noie’s brow creased. “What am I falling for?”

He snickered, and it was not a nice look that was on his face when he answered. “I could eat your skin right now if I wanted to,” he said plainly.

Alarm bells went off in her head. Usually when his eyes went black he just stumbled over his words and blinked a bunch before they turned back. This was different.

“Haha… very funny,” she said with a nervous laugh. “My, uh, my skin isn’t very nutritious. Trust me bro, otherwise I’d have eaten it over cafeteria chicken nuggets anyday.” Her laugh petered off at the scornful glare he was giving her.

“Sealskin is a fucking delicacy,” he spat, making her flinch. “It’s like humans thought ‘hey let’s make our souls even more irresistibly delicious’ and then selkies happened. But I’m not gonna eat it yet. Wanna wait until it’s perfectly aged. Got it hidden away in the perfect place ever since I made the deal.”

Noie felt an awful crawling over her skin, but it didn’t feel like the angel this time. “Wow, you’ve been reading some weird books lately, Dippindots. Aren’t selkies some kind of preter? You better keep your voice down or you might go to jail!”

Dipper bared his teeth and growled, literally growled at her. “Shut up -” he started, then cringed and curled up into a ball. “Agh, this human body sucks,” he moaned. “It’s too small and it hurts and you pathetic meatbags taught it how to feel _love_. Why did I do this to myself? Is the sealskin really worth it?”

Noie’s mind raced as she tried to make any sense of what he was saying. “I know, um, I know, um,” she stammered, “I know your head hurts and stuff. Maybe… maybe you should just… not talk until we get home and you can take some medicine? Maybe that would be good?”

“Oh, give me a break!” he snapped. He clutched his head and started clawing at his scalp. “I gotta get out of this thing now. I hate how it makes me act like I did when I was a stupid human. Can’t take another F͇̖͕̬U͙͖̝̟C̳͉̠̼̗ͅK̸̩̬̬ING ͈͓̳Ṃ̧̝O͕͕͍̲ME̹͈̟̤N̲̣̖̙͎̟͖͠T҉̙ ͙͙̣̮OF̣̰̫͓̙͔ ̣I̟̯̘̠̦͚T͎͕̘̠̳̮̣!” The last part was screeched at the top of his lungs and carried itself through her body like an electric shock.

Noie felt every pair of eyes on the bus turn to stare at them. Quick as a whistle, she wrapped her arms and legs around her brother, who had started to thrash around in his seat, and covered his mouth with her hands. “Haha, he’s fine!” she announced to the rest of the bus. Then she hissed in his ear, “Dipper, please stop!”

As if she’d flipped a switch, he immediately stopped moving and the yelling died in his throat. Instead, he just stared at her with those dark, nightmarish eyes that Noie could see nothing familiar in. Lost and confused, it was a bit before she could do anything other than stare back. Then she gulped and asked, “Are you… feeling a little better?”

Still scowling, he wiggled his nose and said something unintelligible. She was about to ask him to repeat himself when she felt a sharp pain in her finger. She yelped and retracted her hand, cradling it in her armpit. “Did you just _bite_ me?”

“That’s what you get for being insolent enough to use my true name against me,” he replied with a smug smile on his face. “Doesn’t matter though. I’ll get out of here eventually. Ford thought he could keep me locked up forever, but I showed him! I’ve got all the time in the world! All I gotta do is wait. Then I’ll finally be me again!”

Noie felt her temples throb with frustration. “Listen, mister, if I’ve gotta use your name and talk down to you like a child then I’m gonna do it! Whatever… whatever that angel did to you, you still don’t get to be a jerk like this!” Seeing nothing but malice on his face, she teared up and whispered, “Come on Dipper, please come back. Whatever’s happening to you, you gotta fight it. This can’t be the real you. Please, Dipper. Please…”

He continued to sneer at her, but as she started to cry, something in his face twisted. He blinked, and his eyes were back to normal. To her surprise, he went limp in her grasp and she had to strain to prevent him from falling out of the seat. She pulled him back up and leaned him against the window again.

“...Dipper?” she tried.

No answer. All she heard was his shallow breathing. She paused, then folded herself up right in her own seat.

What… had just happened? What on _Earth_ was going on? She’d seen Dipper get plenty of headaches before, but he’d never acted like _that_ before. She ran through a million scenarios in her head trying to figure it out. Did the angel possess him? Could angels do that? Did he get swapped out with a shapeshifter and no one noticed? Did his words mean something or was he just speaking gibberish? Why did calling him by his name make it stop?

Could he actually be a…?

“Noie?”

Noie’s head shot up at the sound of her brother murmuring. “Yeah?” she replied cautiously.

“Mmmm… are we home yet?” he said with a groan. “Think I… think I fell asleep.”

Her lip trembled, and she avoided looking at him. “No, uh. Still a few more stops.”

“That… blows,” he breathed. “I need… um… ibuprofen.”

“There’s some at home, I think. We’re almost there.”

“Cool… Thanks.”

The sound of his breathing became slow and heavy. Noie chanced looking around at him and saw that his eyes were closed and he was thrumming his fingers against his temples. She just watched him, taking some deep breaths herself, and tried to reconcile what she was seeing before her with what had just happened.

“Hey, Noie?”

Noie twitched as her brother’s eyes flickered back open, and almost tore her gaze away from him again. But she found herself staring deep into them, paying attention to the white and the brown, feeling comforted by how normal it was, and relented. “Yeah?”

“...I love you. Very much.”

Noie’s breath hitched. She slowly reached over and slipped her hand into his. Voice cracking, she replied, “I love you too, bro bro.”

He smiled weakly, then closed his eyes again. They stayed closed for the rest of the bus ride. At home, she helped him upstairs into bed and got him some medicine. When it seemed like he’d fallen asleep she left the room, closing the door behind her, and just sat on the floor with her back to the wall. Her mind still buzzing, she tried to calmly replay everything that had happened.

_“It’s funny that you’re falling for this.”_

Up until then, there really wasn’t any evidence that the angel wasn’t just full of shit. But this had really shaken her.

_“This human body sucks!”_

She ground her teeth together and shoved her palms into her eyes so she wouldn’t cry. It didn’t work.

“ _I’ll get out of here eventually. Then I’ll finally be me again._ ”

It wasn’t fair. It wasn’t fair! If he really was a… then she’d be all alone, wouldn’t she? Sure she had Grandma and Grandpa but that really wasn’t the same as a sibling, a peer, a best friend! How could he take that away from her by being…?

 _“You_ are _smart and creative and you should get to feel like it.”_

Their conversation from lunch floated back into her head. He seemed to really care about her -- care about how she felt and whether she felt loved. Was that something that demons did? If he was a demon he must’ve been a really well behaved demon, other than when the angel made him go crazy on the bus. Like, he definitely _wasn’t_ a demon, but if he was, like...

_“Thanks for looking out for me. Mystery Twins forever?”_

Picking her head up, she wiped the tears from her eyes. Whoever it was that was saying those awful things on the bus, it wasn’t her brother. She knew what the real Dipper was like. So it was best not to dwell on it, right? Everything was fine. There was nothing to worry about.

(A few months later, when she watched the angel drive its sword down into Dipper’s chest and his body peeled away, she remembered these thoughts. Even as the demon rose, cackling, from the goopy remains of her brother, she still wasn’t sure if she’d been wrong.)


End file.
